Is 85 Prime?
Check if 85 is a prime number. A prime number is only divisible by 1 and itself.
Result:
✗ NO — 85 is NOT a prime number
Step-by-Step Solution
Step 1
What is a Prime Number?
A prime number is a natural number greater than 1 that has exactly two factors: 1 and itself.
To check if 85 is prime, we need to verify that no number from 2 to √85 divides it evenly.
Step 2
Determine Testing Range
Since 85 is odd, we only need to check odd divisors.
We only need to test up to √85 ≈ 9.22, which rounds down to 9.
If 85 has a factor larger than √85, it must also have a corresponding factor smaller than √85.
Step 3
Test Odd Divisors
Testing: 3, 5, 7, ... up to 9
85 ÷ 3 = 28 remainder 1
85 ÷ 5 = 17 (no remainder!)
We found that 5 divides 85 evenly!
Step 4
Conclusion
85 = 5 × 17
Since 85 has factors other than 1 and itself, 85 is NOT a prime number.